Devastating and disfiguring facial injuries can result from gunshot wounds and motor vehicle accidents as well as from cancer surgeries of the head and neck or breast. The most advanced reconstructive procedures involve distant transfer of tissue including bone, periosteum, skin, muscle and vasculature followed microsurgical anastomosis of pre-existing blood vessels to the grafted tissue, referred to as free or buried flaps. We propose to develop an optical instrument that quantitative monitoring of reconstructive tissue blood perfusion and oxygenation. Four fiberoptic tissue-patches placed within (or atop) tissue grafts connect to the hemodynamic monitor measuring oxygenation and blood flow rate at each location: 1. At a feeding artery; 2. At the exiting vein; 3. Within the capillary bed of the fap; and 4. At the surface of the skin. Each probe will provide the surgeon with direct measures of the rate of vascular flow, total blood volume (hemoglobin concentration) and the blood oxygenation. These measurements will enable the microsurgeon to transit from subjective, non-quantitative assessment of flap health to direct quantitative measurements of flap health. Two pig model studies will be performed. The first study involves surgical creation of a free flap containing a single artery for inflow and single vein for outflow. An occluding device that applies a well-defined amount of occlusion - either to the artery, or the vein - will be used to occlude th vessels while blood flow and oxygenation measurements will be obtained simultaneously at four different sites within the flap: at the artery, at the vein, within the flap bed, and at the skin. hese studies will be short non-survival procedures. In the second study, tissue flaps will be created containing the implanted optical devices and be used to monitor the flap viability at the four site as before, for one week post-surgery.